Elastomeric Emitter And Methods Relating To Same

ABSTRACT

An irrigation drip emitter, and methods relating to same, are provided for delivering irrigation water from a supply tube to an emitter outlet at a reduced and relatively constant flow rate. The emitter having at least one movable member for compensating for fluctuations in supply line fluid pressure. In one form the movable member includes a tapered baffle section movable between a first position wherein fluid is allowed to flow over the tapered baffle section and a second position wherein fluid is prevented from flowing over at least a portion of the tapered baffle section and the tapered baffle section effectively lengthening the extent of a pressure reduction passage. In another form, first and second movable members are provided for compensating for such pressure fluctuations. In another form, a plurality of inputs are provided which are movable between first and second positions to compensate for such pressure fluctuations.

FIELD

The present invention relates to irrigation drip emitters, and more particularly, to multiple irrigation drip emitters mounted to a supply tube to form an irrigation assembly or system.

BACKGROUND

Drip emitters are commonly used in irrigation systems to convert water flowing through a supply tube at a relatively high flow rate to a relatively low flow rate at the outlet of each emitter. Each drip emitter generally includes a housing defining a flow path that reduces high pressure water entering the drip emitter into relatively low pressure water exiting the drip emitter. Multiple drip emitters are commonly mounted on the inside or outside of a water supply tube. In one type of system, a large number of drip emitters are mounted at regular and predetermined intervals along the length of the supply tube to distribute water at precise points to surrounding land and vegetation. These emitters may either be mounted internally (i.e., in-line emitters) or externally (i.e., on-line or branch emitters). Some advantages to in-line emitters are that the emitter units are less susceptible to being knocked loose from the fluid carrying conduit and the conduit can be buried underground if desired (i.e., subsurface emitters) which further makes it difficult for the emitter to be inadvertently damaged (e.g., by way of being hit or kicked by a person, hit by a lawnmower or trimmer, etc.).

In addition to the advantages of in-line emitters, subsurface drip emitters provide numerous advantages over drip emitters located and installed above ground. First, they limit water loss due to runoff and evaporation and thereby provide significant savings in water consumption. Water may also be used more economically by directing it at precise locations of the root systems of plants or other desired subsurface locations.

Second, subsurface drip emitters provide convenience. They allow the user to irrigate the surrounding terrain at any time of day or night without restriction. For example, such emitters may be used to water park or school grounds at any desired time. Drip emitters located above ground, on the other hand, may be undesirable at parks and school grounds during daytime hours when children or other individuals are present.

Third, subsurface emitters are not easily vandalized, given their installation in a relatively inaccessible location, i.e., underground. Thus, use of such subsurface emitters results in reduced costs associated with replacing vandalized equipment and with monitoring for the occurrence of such vandalism. For instance, use of subsurface emitters may lessen the costs associated with maintenance of publicly accessible areas, such as parks, school grounds, and landscaping around commercial buildings and parking lots.

Fourth, the use of subsurface drip emitters can prevent the distribution of water to undesired terrain, such as roadways and walkways. More specifically, the use of subsurface drip emitters prevents undesirable “overspray.” In contrast, above-ground emitters often generate overspray that disturbs vehicles and/or pedestrians. The above-identified advantages are only illustrative; other advantages exist in connection with the use of subsurface drip emitters.

Although some advantages of subsurface emitters are described above, it would be desirable to provide an improved in-line drip emitter design that can be used in both subsurface and above ground applications. For both applications, there is a need to provide for a relatively constant water output from each of the emitters in the irrigation system. More specifically, it is desirable to provide pressure compensation so as to ensure that the flow rate of the first emitter in the system is substantially the same as the last emitter in the system. Without such flow rate compensation, the last emitter in a series of emitters will experience a greater pressure loss than the first. Such pressure loss results in the inefficient and wasteful use of water.

There is also a need in the irrigation industry to keep drip emitters for both subsurface and above ground applications from becoming obstructed, which results in insufficient water distribution and potential plant death. Obstruction of an emitter may result from the introduction of grit, debris, or other particulate matter from debris entering the emitter through the supply tube. It is therefore desirable to have an inlet and/or other structures that are of a design to deflect particles that might otherwise clog flow passages in the body of the emitter. The flow through area of the inlet, however, must also be large enough to allow proper functioning of the drip emitter.

It is also desirable to provide a drip emitter that minimizes parts and assembly as this will not only make the component less complicated to construct and likely save on material costs, but will also reduce the number of emitters that do not perform as desired due to misaligned parts, etc. Drip emitters are commonly formed of multi-piece components (e.g., two or more-piece housing structures with separate flexible diaphragms, etc.) that require individual manufacture of the various parts of the emitter and then assembly of the parts prior to mounting to the supply tube. Even slight misalignment of these components during assembly may result in a malfunctioning drip emitter. Thus, in addition to the above needs, it would be desirable to reduce the number of components required to make the emitter and the manufacturing steps and time it takes to create a finished product.

Lastly, it is also desirable to provide a drip emitter that minimizes the amount of disturbance the emitter causes to the fluid flowing through the drip line or conduit to which the emitter is connected. Larger cylindrical emitters are available in the marketplace for in-line emitter applications, however, these emitters interfere with the flow of the fluid traveling through the drip line or tube and introduce more turbulence to the fluid or system due to the fact they cover and extend inward from the entire inner surface of the drip line or tube. The increased mass of the cylindrical unit and the fact it extends about the entire inner surface of the drip line or tube also increases the likelihood that the emitter will get clogged with grit or other particulates (which are more typically present at the wall portion of the tube than in the middle of the tube) and/or that the emitter itself will form a surface upon which grit or particulates will build-up on inside the drip line and slow the flow of fluid through the drip line or reduce the efficiency of this fluid flow. Thus, there is also a need to reduce the size of in-line emitters and improve the efficiency of the systems within which these items are mounted.

Accordingly, it has been determined that the need exists for an improved in-line emitter and methods relating to same which overcomes the aforementioned limitations and which further provides capabilities, features and functions, not available in current bases and methods, and for an improved method for doing the same.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of several embodiments of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings.

FIGS. 1A-F are perspective, top, front, rear, bottom and right end views, respectively, of a drip emitter embodying features of the present invention, with the perspective and right end views illustrating the emitter bonded to the inner side of a drip line or tube (shown in broken line), the opposite end view (i.e., left end view) being a mirror image of the end view illustrated;

FIGS. 1G-H are cross-sectional views of the emitter of FIGS. 1A-F taken along line i-i illustrated in FIG. 1B, with FIG. 1G illustrating the tapered portion of the inner baffle wall at its low pressure position to show how fluid can flow over the top thereof, and FIG. 1H illustrating the tapered portion of the inner baffle wall at its high pressure position to show how fluid is prevented from flowing over the top thereof;

FIGS. 1I-J are charts illustrating the amount of deflection of the tapered portion of the inner baffle wall per increase in pressure at points 1 and 2 along the tapered portion as illustrated in FIG. 1B, with FIG. 1I illustrating deflection vs. pressure for an elastomeric emitter body material having a Durometer value of 50 and FIG. 1J illustrating deflection vs. pressure for an elastomeric emitter body material having a Durometer value of 75.

FIGS. 2A-D are perspective, top, rear and front views, respectively, of an alternate drip emitter embodying features of the present invention wherein a tongue and fork type arrangement is used instead of a single tapered portion to compensate for pressure fluctuations that the emitter is exposed to when inserted in a supply line, the end and bottom views of this embodiment looking similar to those of the embodiment of FIGS. 1A-F;

FIGS. 3A-D are perspective, top, front and rear views, respectively, of an alternate drip emitter embodying features of the present invention wherein inlet openings of varying heights are used to compensate for pressure fluctuations that the emitter is exposed to when inserted in a supply line;

FIGS. 3E and G are additional rear and perspective views, respectively, of the embodiment of FIGS. 3A-D wherein FIG. 3E illustrates the inlet opening sleeves at a higher pressure position showing at least some of the inlet openings being closed to compensate for an increase in pressure and FIG. 3G illustrates the embodiment of FIGS. 3A-D from an rear right perspective instead of the front right perspective illustrated in FIG. 3A;

FIG. 4 is a perspective view of an alternate drip emitter and drip line embodying features of the present invention and illustrating an emitter with a baffle design which opens and closes in a non-sequential manner;

FIGS. 5A-B are perspective views of an alternate drip emitter and drip line embodying features of the present invention wherein the pressure-reducing flow channel is made-up of baffles with flexible teeth that move in response to fluid flow through the emitter body;

FIG. 6A is a perspective view of an alternate drip emitter and drip line embodying features of the present invention wherein the pressure-reducing flow channel is made-up of baffles with hollow teeth or teeth that enlarge as fluid pressure increases within the supply line so that the pressure-reducing flow channel has a first cross-section at lower fluid pressures and a second cross-section, smaller than the first, at higher fluid pressures to compensate for the increase in fluid pressure so that the emitter and drip line trickle fluid at a generally constant or desired rate;

FIGS. 6B-C are perspective views of a portion of the flow channel of FIG. 6A illustrating the hollow teeth of the baffle partially enlarged and fully enlarged, respectively, in response to increasing fluid pressure showing how the cross-section of the pressure-reducing flow channel in FIG. 6B has a smaller cross-section than that illustrated in FIG. 6A due to an increase in fluid pressure and showing how the cross-section of the pressure-reducing flow channel of FIG. 6C is even smaller yet than that illustrated in FIG. 6B due to a further increase in fluid pressure; and

FIG. 6D is a perspective view of a portion of the bottom of the emitter illustrated in FIG. 6A showing the underside of the hollow teeth members of the baffle and how such surfaces are exposed to the fluid and are affected by an increase in fluid pressure.

Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIGS. 1A-F, a drip irrigation emitter 10 is provided for distributing water from a fluid supply source or conduit, such as drip line or tube 70, at a low flow rate. The drip line 70 carries pressurized fluid throughout an irrigation system and preferably includes numerous emitters 10 spaced apart at predetermined intervals in the dip line 70 in order to allow the drip line 70 to be placed above or below ground to water and/or treat grass, plants, shrubs, trees or other landscaping, or to water agricultural crops of various kinds. In the form illustrated, the emitter 10 includes an integral body 20 which defines an inlet 30 connectable to a source of pressurized fluid, an outlet 40 for discharging the fluid from the emitter body 20, and a pressure reducing flow channel or passage 50 between the inlet 30 and outlet area 40 for reducing the flow of fluid discharged through the outlet 16. In addition, the emitter body 20 defines a pressure compensating member 60 for reducing a cross-section of the flow channel in response to an increase in pressure of the pressurized supply line fluid.

In the form illustrated, the emitter body 20 is made of an elastomeric material, such as a thermoplastic or thermosetting elastomeric material like materials that use ethylene, propylene, styrene, PVC, nitrile, natural rubber, silicone, etc., to form a polymer or copolymer. In a preferred form, the elastomeric material is made of thermoplastic polyolefin (TPO) and silicone rubber. This combination helps create an emitter and drip line that is capable of withstanding the high temperatures and harsh chemicals the emitter may be subjected to while in use. In addition, the emitter is made of a singular or unitary construction rather than having a multi-part construction and/or requiring the assembly of housing parts, diaphragms, etc. This simple construction makes it easier to manufacture the emitter and makes the emitter more grit-tolerant. More particularly, the simple and flexible construction of the emitter can easily process grit or other particulates by expanding to process the grit (aka burping) due to the fact there are no additional housing portions to prevent such expansion. This simple construction also allows the emitter to be flushed more easily by allowing line pressure to be increased to process grit out of the emitter without concern for damaging the emitter because there are no additional pieces, such as multi-part housings, that limit the amount of movement the emitter can make before breaking or coming apart.

Whereas in conventional emitters, even those having two-piece housings, diaphragms and metering grooves to assist in the flushing of grit, the emitter typically reaches a state where further increases is pressure will not increase processing of grit. For example, in conventional emitters, at a certain point of fluid pressure, the pressure on both sides of the diaphragm will eventually become equal and the emitter will cease processing or burping the grit. In the form illustrated, however, the disclosed emitter will continue to process grit with increases in pressure well beyond when conventional emitters stop processing grit (e.g., when this state of equal pressures on opposite sides of the diaphragm are reached). Thus, line pressure can simply continue to be increased in order to drive grit through the emitter body. The elastomeric nature of the emitter body 20 further helps flushing or burping particulates or grit even when simply turning on and off the supply line.

As best illustrated in FIGS. 1E-F, the body 20 defines a plurality of slots 21, 22, 23 and 24, extending longitudinally along the bottom surface of the emitter body 20 which are separated by protrusions, such as guide ribs 25, 26, 27, 28 and 29. The outer most guide ribs 25 and 29 are positioned on the periphery of the bottom surface of emitter body 20 while the inner most ribs 26-28 are positioned on an interior portion separated from the periphery by inlet channel 31. In a preferred form, the inlet channel 31 is sized to deflect foreign materials from obstructing the inlet 30 or entering the emitter body 20 and guide ribs 25-29 have at least one tapered end and run parallel to the longitudinal axis of the emitter body 20 to further help deflect foreign materials from obstructing the inlet channel 31 or entering the emitter body 20. In the form illustrated, the inlet channel 31 extends continuously around or at a perimeter region of the emitter body 20 and empties into the inlet 30. More particularly, in the form illustrated, the inlet channel 31 is a generally oval shaped raceway recessed in the bottom surface of the emitter body 20 having curved ends 31 a, 31 b and longer straight-aways 31 c, 31 d that run longitudinally along the bottom of body 20. The inlet channel has a generally rectangular cross-section and opens into the inlet 30 via a rectangular shaped opening.

The recessed nature and length of inlet channel 31 helps prevent grit or other particulates from entering into the inlet 30 that could clog the emitter 10 or form obstructions preventing the emitter 10 from operating in the desired manner. More particularly, once installed in the drip line 70, pressurized fluid flows along the bottom side of the emitter body 20 with some fluid entering into the raceway of inlet channel 31 and traveling about the periphery of the emitter body 20 and then, ultimately, into the inlet opening 30. In this manner, the side walls of channel 31 serve to deflect grit and other particulates in the fluid from entering into the inlet channel 31 and into the inlet opening 30. This prevents the emitter 10 from getting clogged and/or having obstructions enter the emitter 10 that might otherwise negatively affect or compromise the desired operation of the emitter. The circular flow that is created by the inlet channel 31 further helps ensure that larger particulates that might fit within the inlet channel 31 will fall out of or be flushed from the channel 31 as the fluid races about the raceway before the fluid enters into the inlet opening 30.

The guide ribs 25-29 serve the dual function of assisting with the mounting of the emitter body 20 into the irrigation drip line and further help deflect grit or particulates in the pressurized fluid away from the inlet channel 31 and inlet opening 30. More particularly, one or more of the guide ribs 25-29 may be used by an insertion tool to align and insert the emitter body 20 into the drip line 70 as the drip line is being extruded. In a preferred form, this is done as the drip line 70 is being extruded so that the upper surfaces of the emitter body 20 are bonded or welded to the drip line 70 while the drip line is hot and before it begins to cool. The guide ribs 25-29 may also be tapered or pointed to assist in the initial loading of the emitter body 20 from a bowl sorter and into the inserter or loader used to insert the emitter body 20 into the freshly extruded drip line 70. Such tapering further assists with getting fluid in the supply line to flow between the narrow passages defined by the ribs 25-29 without causing too much disturbance or adding too much turbulence to the fluid flowing through the supply line 70.

In the form illustrated, the guide ribs 25-29 also help prevent grit or other particulates in the pressurized fluid from entering into the inlet channel 31 and inlet opening 30. More particularly, like the sidewalls of inlet channel 31, the ribs 25-29 create narrowed passageways which help deflect larger particulates away from the inlet channel 31 and inlet opening 30. Thus, the ribs 25-29 deflect away larger particulates from the inlet channel 31 and inlet opening 30 and the sidewalls of inlet channel 31 deflect away smaller particulates that are capable of fitting into the narrowed passageways defined by the ribs 25-29. This prevents the emitter 10 from getting clogged and/or having obstructions enter the emitter 10 that might otherwise negatively affect or compromise the desired operation of the emitter 10.

In the form illustrated, the inlet opening 30 is generally rectangular in shape and of a desired size to ensure that the emitter 10 receives a desired amount of fluid at a desired fluid flow rate in order to operate as desired. In alternate forms, however, the inlet opening 30 may be designed in a variety of different shapes and sizes to accommodate specific desires or applications. For example, in alternate forms, the inlet opening may be designed as more of an elongated slot or slit, or plurality of slot-like openings as illustrated in FIG. 4 (which will be discussed further below), for receiving fluid but further deflecting grit or particulates that are small enough to pass through the walls of inlet channel 31 or it may be designed to cooperate with the pressure-reduction flow channel 50 to start reducing the flow and pressure of the fluid as it enters the emitter body 20 (e.g., the inlet may form a tortuous passage that leads to the pressure-reduction channel 50). Similarly, the inlet channel 31 may be designed in a variety of different shapes and sizes. For example, instead of a generally oval shape, the inlet channel 31 may be designed to be a smaller slot that extends over a small portion of emitter body 20 instead of traveling about a periphery of the bottom of the emitter body 20, or may be designed with a zigzag pattern to form a tortuous path to further assist in reducing pressure of the fluid passing through the emitter body 20 (similar to that of the flow path 50, which will now be discussed in further detail).

With respect to the fluid that makes it through the passageways defined by ribs 25-29 and into the inlet channel 31, this fluid passes through the inlet opening 30 and enters a pressure-reducing flow channel 50 that produces a significant reduction in pressure between the fluid flowing in the primary lumen of the supply conduit or drip line 70 and the fluid ultimately emptying into and present in the emitter outlet area 40. In the form illustrated, the emitter body 20 defines opposed baffle walls to create the pressure-reducing flow channel and, in a preferred form, has an inner baffle wall 51 that is surrounded by an outer baffle wall 52 which extends about the inner baffle wall 51 in a generally U-shaped manner to form a flow passageway that generally directs the water in a U-shaped direction of travel. More particularly, the inner and outer baffle walls 51, 52 have alternating projections and recesses that form a tortuous passage and cause the fluid flowing therethrough to zigzag back and forth, reducing pressure with each turn the fluid makes. The outer baffle wall 52 is defined by an outer rim or peripheral wall of the emitter body 20 and the inner baffle wall 51 extends from a portion of the outer rim or peripheral wall and into to the middle of the emitter body 20 to form a peninsula about which the fluid flows from inlet 30 to outlet 40. The upper surfaces of the emitter body preferably have a radius of curvature that tracks the radius of curvature of the tube 70 so that the emitter body 20 can be bonded securely to the inner wall of the tube 70 and create an enclosed pressure reduction passage from inlet 30 to outlet 40. In the form illustrated, the tortuous passage is formed via alternating teeth extending from opposing surfaces of the inner and outer baffle walls 51, 52 and has a cross-section that is generally rectangular in shape when the emitter body 20 is bonded to the inner surface of the extruded drip line 70 (keeping in mind that the radius of curvature of the tube 70 will likely make the upper portion of the cross-section slightly curved and the side walls to be slightly wider at their top than at their bottom).

It should be understood, however, that in alternate embodiments the pressure-reducing flow channel 50 may be made in a variety of different shapes and sizes. For example instead of having projections with pointed teeth, the baffles could be made with blunt or truncated teeth, with teeth that are angled or tapered, with curved or squared projections instead of triangular shaped teeth, with projections of other geometrical shapes or geometries, symmetric or asymmetric, etc.

In the form illustrated, the pressure-reducing flow channel 50 also includes an intermediate bath 53 that the fluid pours into as it makes the turn in the generally U-shaped direction of travel which further causes pressure reduction as the water is flowing from a smaller passage to a larger passage in the bath 53. After making the turn, the fluid passes or zigzags through another section of the pressure-reducing flow channel 50 and empties into outlet pool 40.

In addition to the pressure-reducing flow path 50, the emitter 10 further includes a pressure compensating feature 60 which further allows the emitter 10 to compensate for increases in fluid pressure in the primary lumen of the tube 70. More particularly, pressure compensating feature 60 allows the emitter 10 to maintain relatively constant outlet fluid flow and pressure even though the inlet fluid pressure may fluctuate from time-to-time. In the form illustrated, the pressure compensating feature 60 is a two part pressure compensation mechanism that comprises an elastomeric portion 61 capable of deflecting under pressure to reduce the cross-section of the pressure-reducing flow channel 50 and regulate fluid flow through the emitter, and a movable baffle portion 62 capable of changing the length of the flow channel to compensate for changes in supply line 70 fluid pressure.

The elastomeric portion 61 being a deflectable portion of the emitter body 20 that is moveable between a first position wherein at least a portion of the pressure-reducing flow channel 50 is of a first cross-section and a second position wherein the at least a portion of the pressure-reducing flow channel 50 is of a second cross-section, smaller than the first cross-section to regulate fluid flow through the emitter. In the form illustrated, the floor 61 of the flow channel 50 forms an elastomeric portion and raises and lowers in response to increases and decreases in supply line 70 fluid pressure, respectively. Thus, when fluid pressure increases in the supply line 70, the floor 61 of the flow channel 50 is pressed-up or deflected up into the flow channel 50 thereby reducing the cross-section of the flow channel to regulate the flow of fluid through the emitter 10. Conversely, when fluid pressure in the supply line 70 reduces, the floor of the flow channel 50 retreats from the flow channel back to a normal position wherein the floor is not deflected up into the flow channel thereby increasing the cross-section of the flow channel to allow fluid to flow more freely through the flow channel 50.

Although the above embodiment has been described with the floor of the flow path 50 deflecting up into the emitter flow path to reduce cross-section size of the flow path to compensate for increases in fluid pressure, it should be understood that in alternate embodiments other emitter surfaces could be designed to either create this deflection on their own or to cooperate with the floor or other surface so that both deflect in order to compensate for fluid pressure increases. For example, rather than having the floor deflect, the side walls and/or ceiling of the flow channel 50 could be designed to deflect either in combination with any one of these items or on their own as the sole deflecting portion.

The second part of the pressure compensation mechanism 60 comprises a movable structure, such as movable baffle portion 62, which is capable of moving between a first low pressure position wherein the length of the flow channel 50 is of a first distance and a second high pressure position wherein the length of the flow channel 50 is of a second distance wherein the length of the flow channel is longer than the first distance to compensate for increase pressure in the supply line 70. More particularly, in the form illustrated, the movable baffle portion 62 deflects up and down with the floor of the flow channel 50 to sealingly engage and disengage the movable baffle portion 62 with the inner wall of the supply line 70, respectively, and thereby lengthen or shorten the extent of the flow channel for at least some fluid flowing therethrough to compensate for changes in supply line fluid pressure.

As best illustrated in FIGS. 1C, D and G, the movable baffle portion 62 comprises a tapered portion of the central or inner baffle wall 51 that tapers down away from the inner surface of supply line 70 so that at lower fluid pressures in supply line 70, fluid flows through the inlet 30 and first section (or upstream section) of flow channel 50 and then over the top of the tapered baffle section 62, through the second section (or downstream section) of the flow channel 50 and then into outlet pool 40. Fluid may flow through the remaining portion of the flow channel 50 including intermediate bath 53 (located between the upstream and downstream sections of the flow channel 50), but it does not have to nor does all of the fluid flow through these portions of the flow channel 50 due to the gap between the upper surface of the tapered inner baffle wall section 52 and the inner surface of tube 70. As fluid pressure increases in the fluid supply line 70 and as best illustrated in FIG. 1H, the floor of the flow channel 50 starts to deflect upwards and into the flow channel 50 moving the tapered baffle section 62 toward the inner surface of tube 70 thereby reducing the gap between these two until the upper surface of the tapered baffle section 62 sealingly engages the inner wall of the tube 70 thereby preventing fluid from flowing over the top of the tapered baffle section 62 and lengthening the amount of the flow channel 50 through which all of the fluid must flow and reducing fluid pressure and flow due to same.

The emitter body 20 further defines an outlet area 40 which forms a pool into which the fluid that passes through inlet 30 and tortuous passage 50 and pressure compensation mechanism 60 collects or gathers. An outlet in outer supply line 70, such as opening 71, provides access to the fluid collected in the outlet pool 40 and, more particularly, provides an egress for the fluid to trickle or drip out of emitter 10.

Since the emitter 10 is made of an integral body 20, the outlet area 40 is provided with obstructions or stops, such as posts or nubs 41, that prevent the outlet are 40 from collapsing when the fluid pressure of supply line 70 raises to a level sufficient for deflecting the floor of the flow channel 50 into the flow channel 50 to reduce the cross-section of same and regulate fluid flow through the flow channel (or as the movable structure 62 moves from the first or low pressure position to the second or high pressure position). In the form illustrated, the posts 41 extend away from the body 20 and are generally frustoconical in shape to make the posts easier to mold when the body 20 is molded. In addition, in a preferred form, the upper surfaces of the posts 41 have a radius of curvature common to the radius of curvature of the upper surfaces of baffles 51, 52 and that corresponds with a second radius of curvature of the inner wall of tube 70. The solid nature of the baffle walls 51, 52 and outer rim or peripheral wall of emitter body 20 likewise prevent these portions of the emitter body 20 from collapsing when the fluid pressure of supply line 70 pushes the floor of the flow channel 50 into the flow channel.

Although the form illustrated in FIGS. 1A-D shows the outlet 71 of outer tube 70 as a round opening, it should be understood that in alternate embodiments this may be provided in a variety of different shapes and sizes. For example, in one form the outer tube outlet 71 may be provided in the form of a slit, such as an elongated narrow oval shape, instead of a round hole. In other forms, the outer tube outlet 71 may further define a pressure reducing passageway such as a tortuous or zigzag passage.

By using a unitary emitter body 20 to form the inlet 30, flow channel 50, outlet 40 and pressure compensating mechanism 60 rather than requiring multiple parts to be constructed and assembled to form such features, the emitter 10 is much easier to manufacture and provides significant cost savings due to the reduction in parts and materials, and assembly time. The body 20 may be made of any type of material capable of allowing for this type of movement for pressure compensation. In a preferred form, however, the body 20 is made of TPO having a Durometer reading ranging between 25 and 100, with the Durometer reading preferably being between 50 and 75. In FIGS. 1I-J, data is provided for the amount of deflection per increase in pressure for materials having Durometer readings of 50 and 75, respectively. In these examples, data was collected at location points 1 and 2, as indicated in FIG. 1B, with the distance (or gap) between the inner surface of tube 70 and the upper surface of the tapered inner baffle wall portion 62 being thirty thousandths of an inch (0.030″) at location point 1 and thirteen thousandths of an inch (0.013″) at location point 2, and the floor thickness of flow channel 50 being eight thousandths of an inch (0.008″). These distances being calculated when the tapered baffle wall portion 62 is at its normal position (or low pressure/non-deflected position) as illustrated in FIG. 1G.

As can be seen in comparing FIGS. 1I-J, a quicker movement of the tapered baffle wall portion 62 and corresponding lengthening of the flow channel 50 can be achieved using a material with a lower Durometer reading (e.g., a softer material), whereas a more constant movement (almost linear at times) of the tapered baffle wall portion 62 may be achieved by using a material with a higher Durometer reading (e.g., a harder material). Thus, the specific application the emitter 10 is intended for may play a role in the material selected for emitter body 20 (e.g., if a quicker lengthening of the flow channel 50 is desired a material with a lower Durometer reading will be used, whereas if a more gradual closing of the tapered baffle wall portion 62 and more gradual lengthening of the flow channel 50 is desired a material with a higher Durometer reading will be used, etc.).

In order to ensure the consistency of operation for each emitter 10 mounted to the extruded supply line 70, care is taken to make sure that the various portions of body 20 are constructed with consistent thickness and density from one emitter to the next and that the distances between location points 1 and 2 and the inner surface of supply line 70 are maintained consistently from one emitter to the next. In doing so, the emitters 10 mounted to the supply line 70 should operate in a uniform manner and produce common low pressure fluid flow and flow rates at their respective outputs 40 (e.g., the flow rate of the first emitter mounted in the supply line should operate the same as the last emitter mounted in the supply line).

In an alternate form, the emitter and drip line may be made-up of a multi-part construction and/or use a multi-step manufacturing or assembly process. For example an emitter body of a first type of material may be combined with another type of material (e.g., a structure, a layer, a coating, etc.) that is more easily bonded to conventional drip tubing so that emitter can be bonded to the tubing in a more consistent manner and each emitter is ensured to work similar to one another. More particularly, since soft materials, such as silicon, do not always bond easily to the various types of conventional drip line tubing used in the industry, which is typically polyethylene tubing, the emitter body may be made-up of a combination of soft and hard materials to assist in the bonding of the emitter to the extruded tubing and to provide a process that can repeatedly bond such emitters to extruded tubing so that there is no significant (if any) variance in bonding between the emitters bonded to the tubing.

For example, by combining a soft material like silicon with a hard material like a polyethylene, the hard portion of the emitter may more easily be bonded to the extruded tubing in a uniform and repeatable fashion. Although this form of emitter and tubing may be considered by some to be a two-part construction, it would preferably remain housingless and the soft portion of the emitter would make up the majority of the component. For example, in one form the hard portion of the emitter would simply comprise a polyethylene coating applied to an upper surface of the emitter to assist in consistently bonding the emitter to the inner surface of the drip line tubing in a manner that can be repeated easily from emitter to emitter. Not all of the upper surfaces of the emitter body need to be coated with the polyethylene coating and/or connected to the inner surface of the drip line tubing. Thus, in this example, the emitter continues to comprise a singular or uniform structure through which fluid flows that simply has a bonding layer or agent of polyethylene which assists in connecting the emitter to the inner surface of the drip line tubing. In addition, this configuration would still produce an emitter that can process grit better than conventional emitters, including those with multi-part housings, diaphragms and metering grooves. In alternate forms, true two-piece constructions may be used to form the emitter body if desired with either piece making up a majority of the structure or both making-up equal portions of the structure and/or either piece or both making up portions of the inlet, flow channel or outlet as desired.

Turning now back to FIGS. 1A-F, a housingless irrigation drip emitter 10 is provided for attachment to only a portion of an inner circumference of an inner surface of an irrigation drip line tube 70 having an elastomeric emitter body 20 integrally defining an inlet 30 for receiving pressurized fluid from a fluid supply source, an outlet area 40 for discharging the fluid from the body 20, a pressure reducing flow path 50 extending between the inlet 30 and the outlet area 40 for reducing the pressure and flow of fluid received at the inlet 30 and discharged through the outlet area 40, and a pressure compensating portion 60 for automatically adjusting the pressure and fluid flow reducing effect of the flow channel 50 in response to a change in pressure of the fluid supply source 70, wherein the pressure reducing flow channel 50 includes an inner baffle wall 51 and an outer baffle wall 52 that extends about the inner baffle wall 51 in a generally U-shaped manner. The baffle walls 51, 52 having upper surfaces that have a first radius of curvature that corresponds with a second radius of curvature of an inner wall of the irrigation drip line tube 70, and the inner baffle wall 51 having a first portion of constant height and a second portion 62 of tapering height, the second portion 62 being movable between a first position wherein the upper surface of the second portion 62 is not level with the upper surface of the first portion such that fluid can flow over the upper surface of the second portion at predetermined low fluid pressures and a second position wherein the upper surface of at least a portion of the second portion 62 is level with the upper surface of the first portion and fluid cannot flow over the level upper surfaces of the second portion 62 such that the cross-section of the flow channel is reduced and the length of the flow channel is effectively lengthened.

In the form illustrated, the baffles of the inner and outer baffle walls 51, 52 do not close sequentially when the second portion 62 of inner baffle 51 moves from the first position to the second position, but rather, the teeth of the baffle walls 51, 52 on opposite ends of the flow passage 50 (i.e., some on the inlet end and some on the outlet end) close at the same time. This allows the moving portion 62 of inner baffle 51 to gradually lengthen the extent of the flow passage 50 as supply line fluid pressure increases and to gradually shorten the extent of the flow passage 50 as supply line fluid pressure decreases without having to worry about trying to sequentially close the baffles of the pressure-reducing passage 50.

In alternate embodiments, it should be understood that alternate portions of the emitter body 20 may be moved to compensate for increases in fluid line pressure, either in conjunction with or in lieu of those discussed above. For example, in one alternate form, the emitter body 20 may be designed so that additional sections of the baffle walls 51, 52 may be moved to compensate for pressure increases in the supply line 70. More particularly and as illustrated in FIGS. 2A-D, both the inner baffle wall and outer baffle wall may be designed to move and lengthen the flow path to compensate for increases in supply line fluid pressure. For convenience, items which are similar to those discussed above with respect to emitter 10 in FIGS. 1A-F will be identified using the same two digit reference numeral in combination with the prefix “1” merely to distinguish one embodiment from the other. Thus, the emitter body identified in FIGS. 2A-D is identified using the reference numeral 120 since it is similar to emitter body 20 discussed above. Similarly, the inlet, outlet and pressure-reducing flow channel are identified using reference numerals 130, 140 and 150 since they are similar to the above-mentioned inlet, outlet and flow channel 30, 40 and 50.

While the emitter body 120 of FIGS. 2A-F defines both a pressure-reducing flow channel 150 and a two part pressure compensating mechanism 160 having an elastomeric portion 161 and movable baffle portion 162 like the embodiment of FIGS. 1A-H, the movable baffle portion 163 in FIGS. 2A-F is made up of portions of the inner and outer baffle walls 151, 152 rather than just the inner baffle wall 151. More particularly, the inner and outer baffle walls 151, 152 move to compensate for fluid pressure increases and decreases in the supply line fluid. In the form illustrated, the central or inner baffle wall 151 tapers at its distal end into a tapered tongue-type structure or projection 163 to form a first movable structure and the outer baffle wall 152 defines a mating fork or groove-type structure 164 that corresponds in shape to the tongue-type structure 163 to form a second movable structure.

As best illustrated in FIG. 2F, the tongue and fork or groove structures 163, 164 cooperate with one another so that when the floor 161 of the flow channel 150 rises in response to increases in supply line pressure, the tapered structures 163, 164 both rise toward the inner surface of the tube 170 thereby reducing the amount of fluid that can flow over the upper surfaces of the tapered structures 163, 164 and effectively lengthening the flow channel 150 and reducing the cross-section of the flow channel 150 to compensate for the increase in supply line fluid pressure. Similarly, when the floor 161 of flow channel 150 falls in response to a decrease in supply line pressure, the tapered structures 163, 164 both move away from the inner surface of the tube 170 thereby increasing the amount of fluid that can flow over the top of the upper surfaces of the tapered structures 163, 164 and effectively shortening the length of the flow channel 150 and increasing the cross-section of the flow channel 150 to compensate for the decrease in supply line fluid pressure as illustrated in FIG. 2E.

In the form illustrated, the upper surfaces of the tapered structures 163, 164 never fully seal against the inner wall of the tube 170 when moved to their high pressure position, however, in alternate forms, the tapered structures 163, 164 could be designed such that this occurs if desired. Similarly, the embodiment of FIGS. 1A-H could be designed so that the upper surface of the tapered baffle section 62 does not seal completely against the inner surface of the tube 70, if desired.

It should be understood that in alternate embodiments the first and second movable structures 163, 164 of the inner and outer baffle walls 51, 52 could be swapped so that the inner baffle wall 51 terminated in a groove-type structure and the outer baffle wall 52 defined a tongue-type structure, or in yet other forms both could define other structures meant to correspond with one another or mesh with one another to achieve the same effect of lengthening and shortening the flow channel 50 in response to increases and decreases in supply line fluid pressure, respectively, and if desired, reducing and increasing the cross-section of the flow channel 150 in response to increases and decreases in supply line fluid pressure, respectively. For example, in alternate forms, both the inner and outer baffle walls 51, 52 could define structures that correspond in shape with one another including but not limited to intermeshing U- or V-shaped structures that lengthen the flow channel 150 and reduce the cross-section of the flow channel 150 in response to increases in fluid pressure and that shorten the flow channel 150 and increase the cross-section of the flow channel 150 in response to decreases in fluid pressure.

Thus, with this configuration an irrigation drip emitter 110 is provided for attachment to only a portion of an inner circumference of an inner surface of an irrigation drip line tube 170 having an elastomeric emitter body 120 integrally defining an inlet 130 for receiving pressurized fluid from a fluid supply source, an outlet area 140 for discharging the fluid from the body 120, a pressure reducing flow path 150 extending between the inlet 130 and the outlet area 140 for reducing the pressure and flow of fluid received at the inlet 130 and discharged through the outlet area 140, and a pressure compensating portion 160 for automatically adjusting the pressure and fluid flow reducing effect of the flow channel 150 in response to a change in pressure of the fluid supply source 170, wherein the pressure reducing flow channel 150 includes an inner baffle wall 151 and an outer baffle wall 152 that extends about the inner baffle wall 151 in a generally U-shaped manner. At least some of the upper surfaces of the baffle walls 151, 152 having a first radius of curvature that corresponds with a second radius of curvature of an inner wall of the irrigation drip line tube 170 and the inner baffle wall 151 defines a first tapered baffle structure 163 and the outer baffle wall 152 defines a second tapered baffle structure 164 positioned proximate the first baffle structure 163, with the first and second tapered baffle structures 163, 164 cooperating to form part of the pressure reducing flow channel 150 and the first and second tapered baffle structures 163, 164 tapering in height toward one another and being variably movable between a first position wherein the upper surfaces of the first and second tapered baffle structures 163, 164 are not level with the upper surfaces of the baffle walls with the first radius of curvature so that fluid can flow over the first and second tapered baffle structures 163, 164 and a second position wherein the upper surfaces of the tapered baffle structures 163, 164 move toward and/or are at the same level as the other upper surfaces of the baffle walls with the first radius of curvature and fluid is restricted from flowing over at least a portion of the first and second tapered baffle structures 163, 164 and the cross-section of the flow channel 150 proximate the first and second baffle structures 163, 164 is reduced and the length or extent of the flow channel 150 is lengthened.

In yet other embodiments, the two part pressure compensating mechanism may use other types of movable walls in combination with a deflecting member to compensate for changes in fluid pressure. For example, in the alternate embodiment illustrated in FIGS. 3A-G, the emitter body is designed with a plurality of fluid inlet openings with sleeves or annular walls extending therefrom, which can move in response to increases and decreases in supply line fluid pressure. For convenience, items which are similar to those discussed above with respect to emitter 10 in FIGS. 1A-F and emitter 110 in FIGS. 2A-F will be identified using the same two digit reference numeral in combination with the prefix “2” merely to distinguish this embodiment from the others. Thus, the emitter body identified in FIGS. 3A-F is identified using the reference numeral 220 since it is similar to emitter bodies 20 and 120, and defines an inlet 230, outlet 240 and pressure-reducing flow channel 250, which are similar to those discussed above (i.e., inlet 30, 130, outlet 40, 140, and pressure-reducing flow channel 50, 150). In addition, the upper surfaces of the peripheral wall of emitter body 220, inner and outer baffle walls 251, 252, and nubs 241 all have a first common radius of curvature that corresponds with a second radius of curvature of an inner wall of the irrigation drip line tube 270.

Unlike the embodiments discussed above, however, the inlet 230 of emitter body 220 comprises a plurality of inlet openings 232, 233, 234, 235, 236 and 237. In the form illustrated, the inlet openings 232-237 vary in height, with the initial inlet opening 232 being flush to the floor 261 of the pressure-reducing flow channel 250 and the remaining inlet openings 233-237 having annular walls, such as sleeves or bosses 233 a, 234 a, 235 a, 236 a and 237 a, respectively, that have terminal ends that progressively extend further into the pressure reducing flow channel 250 with the terminal end of each boss moving variably from an open position wherein the terminal end of the boss is not generally level or flush with the first common radius of curvature of the upper surfaces of the baffle walls 251, 252 so that fluid can flow through the boss and into the flow channel 250, and a closed position wherein the terminal end of the boss is generally level or flush with the first common radius of curvature of the upper surfaces of the baffle walls 251, 252 so that fluid is prevented from flowing through the boss and into the flow channel 250.

In a preferred form, the upper surfaces of the terminal end of the bosses 233 a-237 a have a radius of curvature that is the same as the first common radius of curvature of the upper surfaces of baffle walls 251, 252 which corresponds with the second radius of curvature of the inner wall of the irrigation drip line tube 270 so that the bosses 233 a-237 a can close flush against the inner wall of tube 270 and prevent fluid from flowing through the boss and into the flow channel 250 when raised into engagement with the inner wall of tube 270. In addition, the height of the bosses 233 a-237 a are varied so that the inlets 233-237 close sequentially starting with the inlet furthest from the initial inlet opening 232 (i.e., which in the illustrated example is inlet 237) and then moving to the inlet that is the next furthest (i.e., 236), then the next furthest (i.e., 235) and so on. By closing the inlets 233-237 in this order (i.e., starting with the inlet furthest downstream and moving upstream), the emitter body 220 actually lengthens the pressure-reducing passage 250 with each sequential closing for all fluid flowing therethrough which allows the emitter to compensate for increases in the supply line fluid pressure. Conversely, as supply line fluid pressure decreases, the emitter body opens the inlets 233-237 beginning with the inlet furthest upstream and moving downstream, which allows the emitter to shorten the pressure-reducing passage 250 for some of the fluid flowing through the emitter to compensate for the reduction in supply line fluid pressure.

In the form illustrated, it is contemplated that each of inlet openings 233-237 will close during normal operation of the emitter 210 or that the emitter body 220 will be designed such that inlet openings 233-237 will normally close at some point during the operation of the emitter due to expected increases in supply line fluid pressure (i.e., that enough pressure is expected to be reached that will cause inlets 233-237 to close at some point or another). However, it should be understood that in alternate embodiments the emitter body 220 may be designed to only shut one or more of the inlets 233-237 during normal or expected supply line fluid pressure conditions and only having the remaining inlets 233-237 close under extraordinary conditions (e.g., when supply line fluid pressures are reached that are much greater than normal or expected pressures). This can either be done by altering the size of the emitter body 220 or any of its features (e.g., inlet opening, floor thickness, baffle wall size, flow path cross-section, etc.) or by using different materials for body 220 (e.g., materials with different Durometer values, different compositions that make the body 220 harder or less flexible, etc.). Conversely, the emitter body 220 may be made of materials that allow for inlets 233-237 to close more rapidly if desired (e.g., by altering body features and/or selecting different materials as discussed above). In this way, the emitter 10 can be customized for specific applications.

Thus, with this configuration an irrigation drip emitter 210 is provided for attachment to only a portion of an inner circumference of an inner surface of an irrigation drip line tube 270 having an elastomeric emitter body 220 integrally defining an inlet 230 for receiving pressurized fluid from a fluid supply source, an outlet area 240 for discharging the fluid from the body 220, a pressure reducing flow path 250 extending between the inlet 230 and the outlet area 240 for reducing the pressure and flow of fluid received at the inlet 230 and discharged through the outlet area 240, and a pressure compensating portion 260 for automatically adjusting the pressure and fluid flow reducing effect of the flow channel 250 in response to a change in pressure of the fluid supply source 270, wherein the pressure reducing flow channel 250 includes an inner baffle wall 251 and an outer baffle wall 252 that extends about the inner baffle wall 251 in a generally U-shaped manner. With at least some upper surfaces of the baffle walls 251, 252 having a first common radius of curvature that corresponds with a second radius of curvature of an inner wall of the irrigation drip line tube 270, and the inlet 230 includes a plurality of inlet passages 232-237 with each passage 232-237 extending from a surface of the body exposed to the pressurized fluid to the pressure reducing flow channel 250, with at least some of the inlet passages 233-237 extending through bosses each having a terminal end progressively extending further into the pressure reducing flow channel 250, the terminal end of each boss being movable variably from an open position wherein the terminal end of the boss is not level with the upper surfaces of the baffle walls having the first radius of curvature so that fluid can flow through the boss and into the flow channel 250 and a closed position wherein the terminal end of the boss is generally level with the upper surfaces of the baffle walls having the first radius of curvature so that fluid is prevented from flowing through the boss and into the flow channel 250.

It should be understood that in alternate embodiments the sleeves or bosses 233 a-237 a may take on other shapes and sizes as may be desired for specific applications. For example, in some applications inlets with rectangular cross sections may be desired over the round inlets depicted in FIGS. 3A-G. In yet other forms, inlet passages that serve some form of pressure reduction, such as passages that define tortuous paths, may be desired. In still other embodiments, fewer or more inlet openings or bosses may be provided than those shown in FIGS. 3A-G if desired. For example, in FIG. 4, an alternate drip emitter and drip line is illustrated having an inlet made-up of a plurality of inlet openings. In keeping with the above practice, features that are common to those discussed above will use the same two-digit reference numeral, but having the prefix “3” merely to distinguish one embodiment from another.

In the form illustrated in FIG. 4, the plurality of inlets are shaped like elongated openings, such as slits or slots 330, which not only allow fluid to flow through the inlet of the emitter 310, but also help filter or deflect particulates such as grit away from the emitter 310 to help ensure the fluid flowing through the emitter 310 is free of such particulates so that the particulates do not interfere with the operation of the emitter 310. The plurality of openings 330 have longitudinal axes that parallel the longitudinal axis of the emitter 310, however, in alternate forms it should be understood that the plurality of openings may take on a variety of different shapes and sizes and may be oriented in different ways so as not to have longitudinal axes parallel to the longitudinal axis of the emitter 310 (if even having longitudinal axes).

In alternate forms, it should be understood that the inlet or inlets of the emitter may be placed in certain positions to help determine how the emitter will operate. For example, in some forms, an inlet opening may be positioned further upstream to effectively shorten the length of the pressure-reducing flow channel and create an emitter that has a higher fluid flow rate (e.g., four gallons per hour or 4 GPH). In another form the inlet opening may be positioned further downstream to effectively lengthen the pressure-reducing flow channel and create an emitter that has a lower flow rate (e.g., 1 GPH). In still another form, the inlet opening may be positioned somewhere in-between the above mentioned locations to create an emitter with an intermediate pressure-reducing flow channel length that has a flow rate somewhere in-between the other flow rates (e.g., 2 GPH). The changing of this inlet location could be accomplished by having a readily adjustable mold (e.g., one where the location of the inlet opening can be slid or moved between the desired locations) or, alternatively, separate molds could be made for each embodiment (i.e., one for the low flow rate emitter, another for the intermediate flow rate emitter, and another for the high flow rate emitter).

The same may be true for outlet openings. For example, when manufacturing the drip line, the location of the outlet opening may be altered to affect how the emitter will operate. The outlet opening could be located further upstream to effectively shorten the pressure-reducing flow channel and create an emitter with a higher flow rate (e.g., 4 GPH). In another form the outlet opening may be located further downstream to effectively lengthen the pressure-reducing flow channel and create an emitter with a lower flow rate (e.g., 1 GPH). In another form, the outlet opening may be positioned somewhere between the above mentioned locations to effectively create an emitter with an intermediate pressure-reducing flow channel length that operates with a fluid flow rate somewhere between the above-mentioned flow rates (e.g., 2 GPH). The outlet opening may be formed in the drip line tubing before or after the emitter is bonded to the inner surface of the tubing, however, in a preferred form the opening will be formed after the emitter is bonded to the inner surface of the tubing. The opening is typically formed via a die, press, awl or the like. Thus, adjustments to the location of where the outlet opening can be made by adjusting where this puncture occurs in the tubing.

In addition, in some forms color may be added to the individual emitters and/or the drip line and methods of manufacturing same to distinguish these products or product lines from one another or to signify something relating to the items intended use or application. For example, one color may be used to identify an emitter or dip line that drips at a rate of one gallon per hour (1 GPH), another color may be used to identify an emitter or drip line that drips at a rate of two gallons per hour (2 GPH), another color may be used to identify an emitter or drip line that drips at four gallons per hour (4 GPH). In one form, emitters of different flow rates are distinguished by color so that workers can more easily determine which emitters are to be inserted into extruded tubing during assembly in order to obtain a drip line with common emitter drip rates. In another form, the extruded tubing may be made in a specific color or have a marking of a specific color to designate the flow rate of the drip emitters located therein in order to help workers and/or end users distinguish drip lines of different drip rates. In still other forms, both the emitters and the tubing may include color to specify the drip rate or intended application. In other forms, colors may be used to signify the source of fluid to be used with the emitter or drip line or the particular application for which the emitter or drip line is to be used. For example, the color purple is often used to indicate that reclaimed or recycled water is being used. Thus, the emitter or drip line could be marked with this color to indicate that the emitter or drip line is intended for these types of applications or to indicate the type of fluid that is suppose to travel through these types of emitters/drip lines. If desired, any of the embodiments and methods disclosed herein could include the addition of color for such purposes.

Turning back to the embodiment of FIG. 4, it should be appreciated that in this form, the emitter 310 includes a baffle design having teeth extending from the sides of the emitter body 320 toward one another to form the tortuous flow passage 350 without a central baffle portion. The height of each tooth is higher at the sides of the emitter body 320 than at the distal end of each tooth and, as fluid pressure increases, the floor 361 of flow channel 350 moves up toward the inner surface of the tube 370 causing the portions of the teeth closest to the sides of the emitter body 320 to close against (e.g., touch, engage, etc.) the inner surface of the tube 370 first, before gradually closing more and more of each tooth against the inner surface of tube 370 simultaneously until the floor 361 cannot move any further. Thus, rather than closing the baffle teeth consecutively or sequentially against the inner surface of tube 370 to lengthen the pressure-reducing flow passage 350 and compensate for the increase in pressure, this configuration allows each tooth to gradually close against the inner surface of tube 370 simultaneously in response to increases in line pressure thereby lengthening the pressure-reducing flow passage 350 and reducing the cross-section of the pressure-reducing flow channel 350 to form a pressure compensating mechanism 360 that compensates for increases and decreases in line pressure. For convenience, only a portion of tube 370 is illustrated in FIG. 4 so that a portion of the emitter body 320 remains visible, however, it should be understood that the tube 370 would extend over the entire emitter body 320 and that the emitter body 320 would be bonded to the inner surface of the tube in a manner similar to that discussed above.

In the form illustrated, fluid flowing through the drip line 370 enters the emitter 310 via inlet openings 330, travels through the tortuous passage 350 and then exits the emitter 310 via outlet opening 371. The pressure compensating mechanism 360 reduces the cross-section of the flow channel 350 by raising the floor 361 of flow channel 350 and pressing more of the upper surfaces of the baffle teeth into engagement with the inside surface of the tubing 370 as fluid pressure increases, and increases the cross-section of the flow channel 350 by allowing the floor 361 of flow channel 350 to move away from the inner surface of tubing 370 as fluid pressure decreases. This configuration also provides a large central flow path down the middle of the pressure-reducing flow channel 350 which allows for easier processing of grit or other particulates, particularly at start-up and shutdown of fluid flow due to the low pressures associated with same and due to the fact the portion of the flow channel 350 with the largest cross-sectional area will always remain in the middle of the emitter 310 and, specifically, at the longitudinal axis of the flow channel 350.

FIGS. 5A-B are perspective views of an alternate drip emitter and drip line embodying features of the present invention wherein the pressure-reducing flow channel is made-up of baffles with flexible teeth that move in response to fluid flow through the emitter body. In keeping with above practices, items that are common to those discussed above will use the same two digit reference numeral but with the addition of the prefix “4” to distinguish one embodiment from another. In the form illustrated, only a portion of the tube 470 is illustrated in FIG. 5A so that the details of emitter body 420 may be seen, however, it should be understood that the entire emitter body 420 would be inserted within the tube 470 and connected to an inner surface of tube 470.

The emitter 410 includes a plurality of flexible baffle walls extending from opposite sides of the emitter body 420 toward one another and in a staggered arrangement so one wall is not directly opposite a wall on the other side of the emitter body 420. In the form illustrated, the baffle walls form flexible teeth that are much narrower than those discussed above and form generally rectangular walls connected at their base to the floor 461 of the pressure-reducing flow channel 450 and on one side to the side of the emitter body 420. Thus, when fluid flows through the supply line 470, at least a portion of the fluid flows through the inlet opening 430, through the tortuous passage 450 defined by the baffle walls 452, to the outlet 440 and through outlet opening 471. As the supply line fluid pressure increases, the floor of the flow channel 461 moves toward the inner surface of tube 470 driving the tops of the baffle walls into engagement with the inner surface of the supply line tubing 470 and, thereby, restricting or reducing the cross-sectional area of the flow channel 450 and/or increasing the length of the flow channel 450 in response to the increase in pressure in order to compensate for the supply line fluid pressure increase. As the fluid pressure in the supply line continues to increase, the baffle walls 452 closest to inlet 430 flex or bend over in the direction of the fluid flow. This occurs because the pressure of the fluid is always greater than the pressure of the floor 461 raising the baffle walls 452 into engagement with the inner surface of the tube 470. As fluid pressure increases further within tube 470, more and more of the flexible baffle walls 452 will flex or bend in the direction of the fluid flow which can also help the emitter process obstructions such as grit or other particulates by allowing the baffle walls to bend so that the obstructions can be carried through the flow channel and out of the emitter 410. Conversely, when fluid pressure decreases in the supply line 470, the baffle walls cease bending and return to their normal positions (e.g., as illustrated in FIG. 5A) and the floor 461 lowers, allowing the walls 452 to move away from the inner surface of tube 470 and thereby increasing the cross-sectional area of the flow path 450 and/or reducing the length of the flow channel 450 to account for the decrease in fluid pressure. In this way, emitter 410 is equipped with a pressure compensating mechanism 460 like some of the other embodiments discussed herein.

Although the embodiment illustrated shows circular inlets and outlet openings 430 and 471, it should be understood that in alternate embodiments these inlet and outlet openings may take on a variety of different shapes and sizes. In addition, in alternate forms the emitter body 420 may be designed with larger pools or baths located at the inlet 430 and outlet 440 (like the embodiment of FIGS. 1A-H), instead of directly transitioning to the tortuous flow passage 450 as illustrated in FIGS. 5A-B. Furthermore, the flexible baffle walls 452 disclosed in this embodiment could easily be used in any of the other embodiments disclosed herein, just like any of the features of the various embodiments discussed herein could be mixed and matched together to form another embodiment regardless of which embodiment the specific feature is currently illustrated in. Thus, in one form, the flexible teeth 452 may be used in an embodiment more like that shown in FIGS. 1A-H (e.g., with a U-shaped tortuous passage). In still other forms, the flexible teeth 452 may be attached to the emitter body 420 in such a way as to be predisposed to flex or bend in a preferred direction. For example, rather than having the flexible teeth 452 bend in the same direction the fluid flows through the emitter 410, the teeth 452 could be predisposed with an angle causing the teeth 452 to bend in a direction opposite the fluid flow in order to cause more turbulence and interference with the fluid flowing through the emitter 410. As mentioned above, however, in a preferred form of the embodiment of FIGS. 5A-B, the baffle walls 452 will bend in the same direction as the fluid flow.

Yet another embodiment of an alternate drip emitter and drip line in accordance with the invention is illustrated in FIGS. 6A-D. As with the other embodiments discussed herein, this embodiment will use the same two digit reference numeral to refer to items similar to those discussed above, but will include the prefix “5” to distinguish one embodiment from the others. Thus, in the form illustrated in FIGS. 6A-D, the emitter 510 includes an emitter body 520 having an inlet 530, outlet 540 and tortuous flow path 550 extending therebetween; however, unlike the previous embodiments discussed herein, the baffle walls 552 include at least one hollow portion which fills with fluid as the supply line fluid pressure increases in order to reduce the cross-sectional area and/or increase the length of the flow channel 550 to compensate for an increase in fluid pressure.

More particularly, in the form illustrated in FIGS. 6A-D, the teeth 552 of the baffle walls are hollowed-out or define an opening or void 554 in order to allow supply line fluid to fill the void 554 of the hollow teeth 552 (or the space 554 defined by each hollow tooth) and, as supply line fluid pressure increases, to swell or enlarge the size of each tooth 552 by filling this void with pressurized fluid and thereby causing the size of the teeth to grow/expand and reduce the cross-sectional area of the flow channel 550 to compensate for the increase in the fluid pressure. A view of the bottom of emitter body 520 (which is the side of the emitter facing the fluid flowing through supply line 570) is illustrated in FIG. 6D showing the void 554 and illustrating how some of the supply line fluid is able to flow along the bottom surface of the emitter body 520, fill the voids 554 of the hollow teeth, enter the inlet 530 of the emitter and/or continue flowing down the supply line 570.

As fluid pressure increases, the floor of the emitter 561 will also move upwards and, thus, the upper surfaces of the baffle walls 552 will gradually engage more and more of the inner surface of tube 570 thereby increasing the length of the tortuous passage 550 that the fluid must flow through in order to compensate for the increase in fluid pressure. Conversely, when fluid pressure decreases, the floor 561 will drop, gradually disengaging the baffle walls 552 from the inner surface of the tube 570 and the teeth 552 will shrink or reduce in size to effectively increase the cross-sectional area of the flow path 550 and reduce the length of the tortuous passage that the fluid must flow through to compensate for the reduction in fluid pressure. Thus, like the previous embodiments discussed herein, the emitter 510 is equipped with both a pressure-reducing flow path 550 and a pressure compensating mechanism 560 for ensuring that each emitter operates uniformly and as desired.

In FIG. 6A, the supply line fluid pressure is low and, thus, the teeth of baffle walls 552 are not enlarged and the upper surfaces of the baffle walls are not fully engaged with the inner surface of the supply line tube 570. This reduces the length of the flow channel 550 that the fluid must flow through and allows for the flow channel 550 to have a maximum cross-sectional area. In FIG. 6B, the supply line fluid pressure has increased some to a generally intermediate level of pressure such that the teeth of baffle walls 552 have enlarged a bit and the upper surfaces of the baffle walls nearest the side of emitter body 520 begin to engage the inner surface of supply line tube 570. This increases the length of the flow channel 550 that the fluid must flow through and reduces the cross-sectional area of the flow channel 550 to account for or compensate for the increase in fluid pressure. In FIG. 6C, the supply line fluid pressure has increased further to a high level of pressure such that the teeth of the baffle walls 552 have grown or enlarged to their maximum size (or close to their maximum size) and the upper surfaces of the baffles fully engage the inner surface of the supply line tube 570. This further increases the length of the flow channel 550 that the fluid must flow through (thereby maximizing the amount of pressure-reduction taking place via flow channel 550) and reduces the cross-sectional area of the flow channel 550 to its smallest cross-sectional area to compensate for the increase in fluid pressure. In addition, the baffle teeth 552 in FIG. 6C are shown tipping or bending in the direction of the fluid flow (similar to that shown with respect to the embodiment of FIGS. 5A-B). Thus, with this configuration, the pressure-reducing flow channel has a first cross-sectional area at lower fluid pressures, a second cross-sectional area, smaller than the first, at higher fluid pressures to compensate for the increase in fluid pressure so that the emitter and drip line trickle fluid at a generally constant or desired rate, and a plurality of gradually decreasing cross-sectional areas as the fluid pressure increases from the pressure that exists at the first cross-sectional area to the pressure at the second cross-sectional area.

FIGS. 6B-C are perspective views of a portion of the flow channel of FIG. 6A illustrating the hollow teeth of the baffle partially enlarged and fully enlarged, respectively, in response to increasing fluid pressure showing how the cross-sectional area of the pressure-reducing flow channel in FIG. 6B has a smaller cross-sectional area than that illustrated in FIG. 6A due to an increase in fluid pressure and showing how the cross-sectional area of the pressure-reducing flow channel of FIG. 6C is even smaller than that illustrated in FIG. 6B due to a further increase in fluid pressure; and

In addition to the above embodiments, it should be understood that various methods of manufacturing or assembling irrigation drip lines, methods of compensating for pressure in a supply line (e.g., increases or decreases in supply line fluid pressure), methods of manufacturing an emitter and methods of reducing fluid flow pressure are also disclosed herein. For example, a method of assembling an irrigation drip line is disclosed which comprises providing a drip emitter according to any of the above mentioned embodiments where at least one of the inner and outer baffle walls include a tapered baffle wall section, extruding a drip line tube and inserting the provided drip emitter into the drip line tube as it is extruded such that upper surfaces of the emitter other than the tapered baffle wall section are bonded with an inner surface of the extruded drip line tube to form a sealed engagement so that a pressure reduction flow channel is formed between the inlet and outlet area of the emitter. In a preferred form, the upper surfaces of the non-tapered baffle walls are bonded to the inner surface of the extruded drip line tube to form this sealed engagement so that an elongated tortuous passage is formed between the inlet and outlet of the emitter.

In addition to this method, there are disclosed several methods of compensating for pressure in irrigation drip emitters. For example, a method of compensating for pressure in an irrigation drip emitter is disclosed comprising providing a drip emitter according to any of the above-mentioned embodiments wherein the baffle walls have upper surfaces with a first radius of curvature and the inner baffle wall has a first portion of constant height and a second portion of tapering height that is variably movable between a first low pressure position wherein the upper surface of the second portion is not generally level with the upper surface of the first portion and fluid can flow over the upper surface of the second portion at low fluid pressures and a second high pressure position wherein the upper surface of the second portion is level with the upper surface of the first portion such that fluid is prevented from flowing over the upper surface of the second portion and the cross-section of the flow channel is reduced and the extent of the flow channel is effectively lengthened, and moving the second portion of the inner baffle wall between the first low pressure position wherein the upper surface of the second portion is not level with the upper surface of the first portion and fluid can flow over the upper surface of the second portion at low fluid pressures and the second high pressure position wherein the upper surface of the second portion is level with the upper surface of the first portion so that fluid is prevented from flowing over the upper surface of the second portion to reduce the cross-section of the flow channel and effectively lengthen the extent of the flow channel the fluid has to pass through at high fluid pressure in order to compensate for an increase in fluid supply pressure, and moving variably the second portion of the inner baffle wall toward and/or to the second high pressure position to compensate for an increase in fluid pressure and toward and/or to the first low pressure position to compensate for a decrease in fluid supply pressure.

Alternatively, a method of compensating for pressure in an irrigation drip emitter is disclosed which comprises providing a drip emitter according to any of the above-mentioned embodiments wherein the baffle walls have upper surfaces with a first radius of curvature and the inner baffle wall terminates in a first structure and the outer baffle wall includes a second structure that generally corresponds in shape and/or meshes with the first structure and is positioned proximate the first structure, with the first and second structures tapering in height toward one another and being variably movable between a first low pressure position wherein the upper surfaces of the tapered structures are not level with the upper surfaces of the baffle walls and fluid can flow over the tapered structures at low fluid pressure and a second high pressure position wherein the upper surfaces of the tapered structures are level with the upper surfaces of the baffle walls and fluid is prevented from flowing over the tapered structures to reduce the cross-section of the flow channel proximate the first and second structures and effectively lengthen the extent or amount of the flow channel the fluid has to pass through at high fluid pressure, and moving variably the first and second structures toward and/or to the second high pressure position to compensate for an increase in fluid supply pressure and toward and/or to the first low pressure position to compensate for a decrease in fluid supply pressure.

Alternatively, another method of compensating for pressure in an irrigation drip emitter is disclosed comprising providing an irrigation drip emitter according to any of the embodiments disclosed herein, wherein the baffle walls have upper surfaces with a first radius of curvature and the inlet includes a plurality of inlet openings or passages extending from a surface of the body exposed to the pressurized supply fluid to the pressure reducing flow channel, each inlet passage extending through a boss with a terminal end extending progressively further into the pressure reducing flow channel, each of the terminal ends movable variably between an open position wherein the upper surface of the terminal end of the boss is not at the same general level as the baffle walls (or with the upper surfaces of the terminal end and baffle walls not being at a common radius of curvature) so that fluid can continue to flow through the boss and into the flow channel and a closed position wherein the terminal end of the boss is generally level with the upper surfaces of the baffle walls and has a generally common radius of curvature as the first radius of curvature of the baffle walls so that fluid is prevented from flowing through the boss or inlet sleeve and into the flow channel, and moving variably the inlet openings or terminal ends of the bosses toward and/or to the second high pressure closed positions to compensate for a increase in fluid supply pressure and toward and/or to the first low pressure open positions to compensate for a decrease in fluid supply pressure.

In the above examples, it should be clear that movement of the movable walls or structures to compensate for fluid pressure increases and decreases can either be complete movements from a first limit of travel to a second limit of travel (i.e., from a furthest most open position to a furthest most closed position and vice versa), or alternatively, may simply be movements toward one or more of those limits of travel without those limits actually having been reached (i.e., movement toward a furthest most open position to a furthest most closed position and vice versa). In addition, the material chosen for the emitter body (e.g., 20, 120, 220 above), may be selected such that such movement happens at a desired pace. For example, if a quick opening and closing is desired, a material that is more flexible or has a lower Durometer value may be selected. Whereas, if a slower or more gradual opening and closing (or transitioning from one or the other) is desired, a material that is less flexible or that has a higher Durometer value may be selected.

There also are disclosed herein various methods for processing grit through an emitter or clearing emitters and/or drip lines of obstructions. For example, one method for processing grit comprises providing an emitter of the type discussed above, adjusting the fluid pressure that the emitter is subjected to in a supply line to alter the size or shape of the flow channel to expel any obstructions clogging the emitter (e.g., obstructions clogging an inlet, flow channel, outlet, etc.). In one form this is done by decreasing the fluid pressure to maximize the cross-sectional area of the flow channel and/or create a central flow channel through which any obstructions such as grit or other particulates may be flushed. In another form this is done by increasing the fluid pressure to cause the baffle walls of the flow channel to deflect, bend or tip so that obstructions can pass through the flow channel or be carried out of the emitter via the high pressure fluid passing therethrough.

Thus it is apparent that there has been provided, in accordance with the invention, an elastomeric emitter and methods relating to same that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. 

What is claimed is:
 1. An irrigation drip emitter for attachment to only a portion of an inner circumference of an inner surface of an irrigation drip line tube comprising: an elastomeric emitter body integrally defining an inlet for receiving pressurized fluid from a fluid supply source, an outlet area for discharging the fluid from the body, a pressure reducing flow path extending between the inlet and the outlet for reducing the pressure and flow of fluid received at the inlet and discharged through the outlet area, and a pressure compensating portion for automatically adjusting the pressure and flow reducing effect of the flow channel in response to a change in pressure of the fluid supply source; wherein the pressure reducing flow channel includes an inner baffle wall and an outer baffle wall that extends about the inner baffle wall in a generally U-shaped manner.
 2. The irrigation drip emitter of claim 1 wherein the baffle walls have upper surfaces, each upper surface having a first radius of curvature that corresponds with a second radius of curvature of an inner wall of an irrigation drip line tube, the inner baffle wall having a first portion of constant height and a second portion of tapering height, the second portion being movable between a first position wherein the upper surface of the second portion is not level with the upper surface of the first portion such that fluid can flow over the upper surface of the second portion at predetermined low fluid pressures and a second position wherein the upper surface of at least a portion of the second portion is level with the upper surface of the first portion and fluid cannot flow over the level upper surface of the second portion such that the cross-section of the flow channel is reduced and the length of the flow channel is lengthened.
 3. The irrigation drip emitter of claim 1 wherein the emitter body further defines an obstruction for preventing the outlet area from collapsing under pressure as the upper surface of the second portion of the inner baffle moves from the first position to the second position;
 4. The irrigation drip emitter of claim 3 wherein the obstruction is a post projecting away from the body.
 5. The irrigation drip emitter of claim 1 wherein the emitter body defines a channel at the inlet sized to deflect foreign material from obstructing the inlet or entering the emitter body.
 6. The irrigation drip emitter of claim 5 wherein the inlet further includes a plurality of ribs projecting away from the body to deflect foreign materials from obstructing the inlet or entering the emitter body.
 7. The irrigation drip emitter of claim 6 wherein the channel extends continuously at a perimeter region of the emitter body and emptying into the inlet and the plurality of ribs comprising at least one tapered end and running parallel to a longitudinal axis of the emitter body.
 8. The irrigation drip emitter of claim 1 wherein the baffle walls have upper surfaces, at least some of the upper surfaces having a first radius of curvature that corresponds with a second radius of curvature of an inner wall of an irrigation drip line tube and the inner baffle wall defines a first tapered baffle structure and the outer baffle wall defines a second tapered baffle structure positioned proximate the first baffle structure, the first and second tapered baffle structures cooperate to form part of the flow channel, the first and second tapered baffle structures tapering in height toward one another and being variably movable between a first position wherein the upper surfaces of the first and second tapered baffle structures are not level with the upper surfaces of the baffle walls with the first radius of curvature and fluid can flow over the first and second tapered baffle structures and a second position wherein the upper surfaces of the tapered baffle structures move toward or are at the same level as the other upper surfaces of the baffle walls with the first radius of curvature and fluid is restricted from flowing over at least a portion of the first and second tapered baffle structures and the cross-section of the flow channel proximate the first and second baffle structures is reduced and the length of the flow channel is lengthened.
 9. The irrigation drip emitter of claim 8 wherein the first tapered baffle structure is shaped as a first tongue or fork structure and the second tapered baffle structure is shaped as a second tongue or fork structure, respectively, such that the first and second tapered baffle structures mesh to form a pressure reducing portion of the flow channel.
 10. The irrigation drip emitter of claim 1 wherein the baffle walls have upper surfaces, at least some of the upper surfaces having a first common radius of curvature that corresponds with a second radius of curvature of an inner wall of an irrigation drip line tube, and the inlet includes a plurality of inlet passages with each passage extending from a surface of the body exposed to the pressurized fluid to the pressure reducing flow channel, at least some inlet passages extending through bosses each boss having a terminal end progressively extending further into the pressure reducing flow channel, the terminal end of each boss moves variably from an open position wherein the terminal end of the boss is not level with the upper surfaces of the baffle walls having the first radius of curvature so that fluid can flow through the boss and into the flow channel and a closed position wherein the terminal end of the boss is level with the upper surfaces of the baffle walls having the first radius of curvature so that fluid is prevented from flowing through the boss and into the flow channel.
 11. The irrigation drip emitter of claim 10 wherein the plurality of bosses move from the open position to the closed position such that the plurality of inlet openings are sequentially closed beginning with the inlet opening having the boss that extends furthest into the flow channel and ending with the inlet opening having the boss that extends least into the flow channel.
 12. A method of assembling an irrigation drip line comprising: providing a drip emitter according to claim 1 and where at least one of the inner and outer baffle walls includes at least some tapered baffles; extruding a drip line tube; and inserting the irrigation drip emitter according to claim 1 into the drip line tube as it is extruded such that the non-tapered baffles bond with an inner surface of the extruded drip line tube to form a sealed engagement so that a pressure reduction flow channel is formed between the inlet and outlet area.
 13. A method of compensating for pressure in an irrigation drip emitter comprising: providing a drip emitter according to claim 1 wherein the baffle walls have upper surfaces with a first radius of curvature and the inner baffle wall has a first portion of constant height and a second portion of tapering height that is variably movable between a first position wherein the upper surface is not level with the upper surface of the first portion and fluid can flow over the upper surface of the second portion and a second position wherein the upper surface of the second portion is level with the upper surface of the first portion such that fluid is prevented from flowing over the upper surface of the second portion and the cross-section of the flow channel is reduced and the extent of the flow channel is lengthened; and moving the second portion of the inner baffle wall between the first position wherein the upper surface of the second portion is not level with the upper surface of the first portion and fluid can flow over the upper surface of the second portion and the second position wherein the upper surface of the second portion is level with the upper surface of the first portion so that fluid is prevented from flowing over the upper surface of the second portion to reduce the cross-section of the flow channel and effectively lengthen the extent of the flow channel the fluid has to pass through in order to compensate for a change in fluid supply pressure; and moving variably the second portion of the inner baffle wall toward or to the second position to compensate for an increase in fluid supply pressure and toward or to the first position to compensate for a decrease in fluid supply pressure.
 14. A method of compensating for pressure in an irrigation drip emitter comprising: providing a drip emitter according to claim 1 wherein the baffle walls have upper surfaces with a first radius of curvature and the inner baffle wall terminates in a first structure and the outer baffle wall includes a second structure that generally meshes with the first structure, with the first and second structures tapering in height toward one another and being variably movable between a first position wherein the upper surfaces of the tapered structures are not level with the upper surfaces of the baffle walls and fluid can flow over the tapered structures and a second position wherein the upper surfaces of the tapered structures are level with the upper surfaces of the baffle walls and fluid is prevented from flowing over the tapered structures to reduce the cross-section of the flow channel proximate the first and second structures and effectively lengthen the extent of the flow channel; and moving variably the first and second structures toward or to the second position to compensate for an increase in fluid supply pressure and toward or to the first position to compensate for a decrease in fluid supply pressure.
 15. A method of compensating for pressure in an irrigation drip emitter comprising: providing a drip emitter according to claim 1 wherein the baffle walls have upper surfaces with a first radius of curvature and the inlet includes a plurality of inlet passages extending from a surface of the body exposed to the pressurized supply fluid to the pressure reducing flow channel, each inlet passage extending through a boss with a terminal end extending progressively further into the pressure reducing flow channel, each of the terminal ends moveable variably between an open position wherein the terminal end of the boss is not at the same level with the upper surfaces of the baffle walls with the first radius of curvature so that fluid can continue to flow through the boss and into the flow channel and a closed position wherein the terminal end of the boss is level with the upper surfaces of the baffle walls with the first radius of curvature so that fluid is prevented from flowing through the boss and into the flow channel; and moving variably the terminal ends of the bosses toward or to the closed positions to compensate for an increase in fluid supply pressure and toward or to the open positions to compensate for a decrease in fluid supply pressure.
 16. An irrigation drip emitter for insertion into a drip line tube capable of carrying pressurized fluid comprising: a unitary body defining an inlet, outlet and pressure reduction flow channel connected between the inlet and outlet and having a two part mechanism to compensate for fluctuations in supply line fluid pressure; wherein the first part comprises an elastomeric portion capable of deflecting to reduce a cross section of the pressure reduction flow channel, and the second part comprises movable baffles portions capable of changing the length of the flow channel to compensate for changes in supply line fluid pressure.
 17. An irrigation drip emitter according to claim 16 wherein the pressure reducing flow channel includes an inner baffle wall and an outer baffle wall that extends about the inner baffle wall and the movable baffles comprise a tapered portion of the inner baffle wall that move variably between a first position wherein fluid is allowed to flow over the top of the tapered portion and a second position wherein fluid is prevented from flowing over the top of the tapered portion thereby effectively lengthening the flow channel.
 18. An irrigation drip emitter according to claim 16 wherein the pressure reducing flow channel includes an inner baffle wall and an outer baffle wall that extends about the inner baffle wall, the inner and outer baffle walls each defining tapered structures that correspond in shape with one another and make-up part of the flow channel, at least one of the corresponding tapered structures making up the movable baffles and being movable variably between a first position wherein fluid is allowed to flow over the top of the tapered structure and a second position wherein fluid is prevented from flowing over the top of the tapered structure thereby effectively lengthening the flow channel.
 19. An irrigation drip emitter for bonding with an inner surface of an irrigation drip line tube capable of carrying pressurized fluid comprising: a unitary structure defining an inlet, an outlet, a tortuous passage formed by opposed inner and outer baffle walls extending intermediate the inlet and outlet, and having a two part mechanism to compensate for fluctuations in supply line fluid pressure; wherein the baffle walls have upper surfaces with a first radius of curvature that corresponds with a second radius of curvature of an inner surface of an irrigation drip line tube and the inlet includes a plurality of inlet passages extending from a surface of the unitary structure exposed to the pressurized fluid of a supply line to the pressure reducing flow channel, each inlet passage extending through a boss having a terminal end extending progressively further into the pressure reducing flow channel, each of the terminal ends being variably moveable between an open position wherein the terminal end of the boss is not level with the upper surfaces of the baffle walls with the first radius of curvature so that fluid can continue to flow through the boss and into the flow channel and a closed position wherein the terminal end of the boss is closer to or at the level of the upper surfaces of the baffle walls with the first radius of curvature so that fluid is prevented from flowing through the boss and into the flow channel.
 20. A irrigation drip line assembly comprising: a irrigation drip line tube having an inner surface; a one piece emitter unit of an elastomeric material, the unit having an inlet to receive pressurized fluid, an outlet for discharging the fluid from the unit, a pressure reducing flow channel intermediate the inlet and outlet for reducing the flow of fluid discharged through the outlet, and providing a pressure compensating mechanism for reducing a cross-section of the flow channel in response to an increase in pressure of the pressurized fluid; wherein the pressure reducing flow channel includes an inner baffle wall and an outer baffle wall that extends about the inner baffle wall, the baffle walls having upper surfaces with a first radius of curvature that corresponds to a second radius of curvature of the inner surface of the irrigation drip line tube and are bonded to the inner surface of the irrigation drip line tube to form an enclosed flow channel from the inlet to the outlet of the emitter body. 